Cadence vs Speed and Power required...

Cadence is the number of revolutions of the crank per minute, this is the rate at which a cyclist is pedalling/turning the pedals.
Take a look at the Wikipedia article on bicycle cadence.

There has been much scientific research on optimum cadence. For most people a cadence of 60 to 100 rpm is a comfortable range,
with some sources measuring maximum power at 85 rpm and others at 90 - 95 rpm.

Factors are the degree of fitness of the rider and the degree to which efficiency or peak power are important.

Click on one of the orange buttons above to analyse your ideal gearing for your make of hub or derailleur gearset.